Calculate Angle and Length in Triangle
OK I follow now.
The internal angle between lines a & b is 45-20=25. This angle is opposite c
and is thus Angle-C
Referring to the formula I posted previously
c = SQRT(a^2 + b^2 - 2*a*b*COS((180-A-B)*PI()/180))
change (180-A-B) to 25 and include the known side lengths a & b
= SQRT(35^2+30^2-2*35*30*COS(25*PI()/180))
= 14.8913950730962
Somehow Dana managed to obtain an extra 2dp of precision beyond the
capabilities of my Excel <g
Regards,
Peter T
"Cathy" wrote in message
...
Sorry if I am confusing things by not explaining 100%
This is very usefull to me as my head is hurting going through Trig
websites
trying to remember everything again.
Okay let me try again from scratch
# A B C
1 Side Direction Length
2 Line1 20 35
3 Line2 45 30
4 Line3 ? ?
Three lines form a triangle. Lets call it Triangle ABC with these letters
on
each of the corners
(it is not a right Triangle)
Line1 = a = AB
Line2 = b = BC
Line3 = c = CA
Line1 starts at position 0.0
Line1 is angled at 20 degrees from 0 (0 being horizontal)
Line1 is 35 meters long
Line2 starts at position 0.0 also
Line2 is angled at 45 degrees from 0
Line2 is 30 meters long
The difference in angle between Line1 and Line2 is therefore 25 degrees
Line3 completes the Triangle
Need to calculate angle from 0
Need to calculate length
Therefore using Daves Example the angle of side1 would be 25
If you had:
# A B C
1 Angle Length
2 Side1 25 35
3 Side2 ? 30
4 Side3 ? ?
And therefore I have to calculate three values
If formulas for these three can be provided, then I will be very happy.
Hope this makes a little more sense now. (Wish I could draw it as I see it
in text)
TIA
C
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